Extractor-cover.



H. G. MITCHELL.

EXTRACTOR COVER.

APPLICATION.,

.FILED APR.10.!915.

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HOOPER SONS MANUFACTURING COMPANY,

OF PHILADELPHIA, PENNSYL- VANIA, A CORPORATION OF PENNSYLVANIA.

Ex'rRAcToncovER.

Specicaton of Letters Patent.

Patented May 2, 49ML Application led April 10, 1915. Serial No. 20,421.

To all whom t may concern Be it known that I, HAROLD G. MITCHELL, a citizen of the United States of America, residing at the city of Philadelphia, State of Pennsylvania, have invented certain new and useful Improvements in Extractor-Cov ers, of which the following is a specification.

This invention relates to a cover for centrifugal extractors or separators of the kind which are used in separating liquids or liquids and solids of different specific gravity. The covers or disks are placed over the material or contents of the extractor to prevent the material from escaping and also to keep out foreign matter such as dirt, grease or any substance which may harm the contents of the extractor. These covers are placed on the top of the rotary can or tank which is the main feature of the separator and the object of the invention is to provide an extractor cover of suiiicient strength and durability to resist the wear and the torsional and centrifugal stresses to which the cover is subjected in the rotation of the extractor at the high speeds incident to the separation or extraction of materials by centrifugal action and not subject to deterioration by the action of the liquids treated.

In the drawings I have illustrated the cover in two forms.

Figures l and 2 show a cover intended to be used with the extractor having a central shaft extending upward from the rotary1 separating tank; Figure l being a plan and Fig. 2 a vertical central cross section. Figs. 3 and 4 relate to an extractor cover for use with the under driven or solid type of extractor, having no shaft above.

The extractor cover shown in Figs. 1 and 2 is a fabric disk composed of two thicknesses of cotton duck 1, 2 preferably reinforced centrally by circular pieces of duck 3 and 4, above and below. There is a central aperture 5, for the shaft and this is lined with duck or equivalent material 6, by means of which the edge of the opening is faced. In order that the extractor cover may be conveniently applied and removed, it is slotted radially at 7 from the center to the circumference and a flap 8 to close the slot is inserted between the thicknesses l and 2 and secured by two radial seams 9. The edge of the slotted opening 7, opposite the flap is preferably faced with a piece of material l0, forming a continuation of the facing 6 and this facing is continued along the inner edge of the flap 8 at l1.

The second form shown in Figs. 3 and 4 lacks the feature of the central opening and radial slot and also the central reinforcement as it is for use with an under driven extractor and it is unnecessary to provide for the central shaft.

It is found in practice that the extractor covers in common use yield to the whirl or to the torsion incident to acceleration in attaining the high speeds necessary to the operation of the extractor and tov retardation from these speeds in stopping. This causes wrinkling and twisting of the cover with consequent exposure of the contents of the extractor to the introduction of foreign matter and to loss by splashing and in a short time the covers in common use yield to the stresses and are destroyed. To overcome this difficulty, in the present instance, I have not only used two thicknesses of heavy cotton duck, but have stitched the material with heavy water proof thread along the lines of the stresses, first radially at l2, second on circular lines 13, concentric with the axis of the extractor, and third in U shaped loops 14,v extending inward from the circumference and having the arms radial. The lines of stitching are practically inelastic and do not yield to the stresses set up in the cover in the operation of the extractor. They, therefore serve to reinforce the cover preventing buckling due to the whirl and in addition to their function in preventing stretching of the extractor cover with consequent buckling and exposure of the contents of the extractor as described, they serve to strengthen the fabric along the lines of the destructive forces exerted and hence increase its length of life.

Having thus described the invention what desire to secure by Letters Patent is:

An extractor cover in the form of a fab- K Copies of this patent may be obtained for ric disk composed of a pluralityl of layers l of oluck,` means for strengthening the dlsk consisting of lines of` stitching inthe form of Ushaped loops, the arms of the U being radio1 and other lines extending along diametretl lines and stitching enelreling the disk concentric with the axis.

signed by me at Philadelphmthis 5th day of April, 1915.

HAROLD GOETHE MITCHELL.

Vitnesses:

ABRAM Gr. TATNALL, J. F. ONEILL.

ve cents each, by addressing the Commissioner of Iatents, Washington, D. G. 

